Understanding Socio-Cognitive Impairments in Parkinson's Disease: from Behavioural to Neuroimaging Characterisation

Parkinson's disease (PD) represents the second most prevalent neurodegenerative disorder. Despite notable advancements in the comprehension of its pathophysiology in recent years and the introduction of updated diagnostic criteria that reflect these developments, the comprehensive understanding of its intricate clinical presentation remains to be further investigated and more precisely delineated. A substantial body of evidence from existing literature has consistently demonstrated the presence of non-motor symptoms in patients with PD, including deficits in social cognition. Nevertheless, socio-cognitive dysfunctions in PD remain a relatively underexplored area, and the available tools for assessing these deficits are limited, particularly in the clinical setting. To address this gap in the existing literature, the present doctoral thesis is structured around three key objectives. The first aim is to improve the characterisation of socio-cognitive dysfunctions in PD in the clinical context. Secondly, the objective is to introduce and evaluate the clinical validity of a novel test designed to assess the ability to recognise complex mental states. Finally, the thesis aims to contribute to the elucidation of the neural correlates underlying deficits in mental state recognition in individuals with PD via magnetic resonance imaging. In order to achieve these aims, three behavioural studies (Study 1-3) and one neuroimaging study (Study 4) have been conducted. The results of this doctoral thesis posit that deficits in socio-cognitive processes can be observed in patients with PD from the early stages of the disease and are associated with structural and functional changes in brain areas involved in emotion understanding. Furthermore, this thesis suggests that a detailed characterisation of early socio-cognitive dysfunctions in PD may facilitate the definition of new cognitive phenotypes and potentially the development of new non-pharmacological interventions (Study 5) tailored to the individual's specific needs.